Add myself as a maintainer
Add myself as a maintainer

I am requesting maintainership for the code in the extensions
directories.

Signed-off-by: Matt Spinler <c000c989d08c98662d98f15448f11de169feb92d@us.ibm.com>
Change-Id: Id2f9e286f7b944afcf09bf5b513a63520098fd5d

openbmc/phosphor-logging,openbmc/phosphor-logging,openbmc/phosphor-logging,openbmc/phosphor-logging